Transcript Special Sense

Special Senses
A&P CHAPTER 10
Special Senses
Touch
Taste
Smell
Hearing
Vision
Sensory Receptors
Structures that are stimulated by changes in the environment
Receptors for touch, pain, temperature, pressure
Found all over the body in all types of tissue
◦ Skin
◦ Connective Tissue
◦ Muscle
Sensory Receptors
Specific receptors
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Taste buds of the tongue
Nose
Retina of the eye
Inner ear
Projection of Sensation
◦ Sense organ is stimulated  travels along nerves to brain  registers in the brain  brain sends
sensation back to sense organ
◦ Sensation actually takes place in brain
The Eye
Protected by:
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Orbital socket
Eyebrows
Eyelids
Eyelashes
Lacrimal Duct & Glands
◦ Cleanse & Moisten
Oil Glands
◦ Secretes oily substance that lubricates the eye
Conjunctiva
◦ Thin membrane lining the eyelids & part of the eye
◦ Secretes mucus to help lubricate the eye
The Wall of the Eye
Three Layers
◦ Sclera: Outer layer of the eye, known as the
whites of the eye
◦ Choroid: Middle layer, contains blood vessels
◦ Retina: Innermost layer, image is perceived &
impulses sent to the brain
The Eye
SCLERA
CORNEA
Fibrous capsule that maintains the shape of
the eye
Clear, circular area that lies in front center of
sclera
Protects structure within the eye
“Window” of the eye
Eye muscles attached to sclera
Transparent to permit passage of light rays
◦ Extrinsic Muscles
Pain & touch receptors
The Eye
CHOROID COAT
IRIS
Contain blood vessels that nourish the eye
Colored, muscular layer that surrounds the
pupil
Pupil: Circular opening within the choroid coat
Eye color is related to number & size of
melanin in iris
Intrinsic muscles in iris controls amount of
light entering the pupil
The Eye
LENS
RETINA
Crystalline structure located behind the iris &
pupil
Light sensitive layer
Elastic, disc shaped structure
Location where light rays from an object form
an image
Focuses images on retina
Rods
◦ Specialized cell sensitive to dim light
Cones
◦ Specialized cell sensitive to bright light & color
vision
Pathway of Vision
Images in the light  cornea  pupil  lens  light rays are bent/refracted  retina  rods &
cones pick up stimulus  optic nerve  occipital lobe of brain for interpretation
Eye Disorders
Conjunctivitis (Pink Eye)
◦ Inflammation of the conjunctival membranes
◦ Redness, pain, swelling, discharge of mucus
◦ Bacterial Conjunctivitis Highly contagious
Glaucoma
◦ Excessive intraocular pressuredestruction of retina & atrophy of optic nerve
◦ Mild aching, loss of peripheral vision, halo around light
◦ Occurs with aging
Cataracts
◦ Lens of eye gradually becomes cloudy
◦ Painless, gradual blurring & loss of vision; pupil will appear milky white
◦ Common in individuals over 70
Eye Disorders
Macular Degeneration
◦ Disorder of the retina
◦ Dimming/Distortion of vision
◦ Occurs as a person ages
Detached Retina
◦ Loss of peripheral vision and then loss of central vision
◦ Can occur with age or from a traumatic accident
Diabetic Retinopathy
◦ Leading cause of blindness in American adults
◦ Caused by changes in blood vessels in the retina
Sty
◦ Tiny abscess (inflammation of sebaceous gland) at the base of an eyelash
◦ Red, painful, swollen
◦ Warm, wet compresses to relieve pain & promote drainage
Vision Defects
Night Blindness
◦ Difficult to see at night, rods are affected
Color Blindness
◦ Inability to distinguish colors, cones are affected, inherited
Presbyopia
◦ Lenses lose elasticity due to age  decreases ability to focus on close objects
◦ Common after 40, can be corrected with glasses/contacts
Hyperopia
◦ Farsightedness
Myopia
◦ Nearsightedness
Effects of Aging on the Eye
Decreased ability to focus on fine detail
Slower to adjust to changing light conditions
Peripheral vision and depth perception decline
Loss of visual acuity
The Ear
Picks up sound waves & sends to the auditory center of the brain
Involved in Equilibrium
Three parts
◦ Outer/External
◦ Middle
◦ Inner
Outer Ear
Pinna (Outer part of ear)
◦ Collects sound waves
◦ Directs sound waves to auditory canal
Auditory canal
◦ Glands secrete cerumen (earwax) to protect the ear
Tympanic Membrane (Eardrum)
◦ Separates the outer and middle ear
Middle Ear
Cavity in the temporal bone
Connects with pharynx (throat) through the Eustachian tube
◦ Eustachian tube is responsible for equalizing the air pressure in the middle ear with the outside
atmosphere
Three Tiny Bones are found in the Middle Ear
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Responsible for transmitting sound waves from eardrum to inner ear
Hammer (Malleus)
Anvil (Incus)
Stirrup (Stapes)
Inner Ear
Cochlea
◦ Spiral-shaped passage, contains the cochlear duct
Cochlear Duct
◦ Filled with fluid that vibrates when sound waves strike against it
Organ of Corti
◦ Delicate hair-like cells located in the cochlear duct
◦ Pick up vibrations caused by sound waves against fluid
◦ Transmit vibrations through the auditory nerve to the brain
Semi-Circular Canals (Three)
◦ Help maintain body balance/equilibrium
◦ No role in the sense of hearing
Ear Disorders
Otitis Media
◦ Middle Ear Infection
Otosclerosis
◦ Stapes first becomes spongy, then hardens. Stapes become immovable.
◦ Inherited, common cause deafness among young adults
Tinnitus
◦ Ringing in the ears due to injured auditory cells
Presbycusis
◦ Hearing loss related to aging; Hearing aids can be used
Meniere’s Disease
◦ Condition affecting the semicircular canals of the inner ear, causing vertigo (dizziness)
Effects of Aging
Tympanic membrane becomes fibrous
◦ Reduces the transmission of sound
Degeneration of ear bones, vestibular structure, cochlea, organ of Corti
◦ Affects sensitivity to sound, understanding speech, and balance
Loss of hearing high-pitched sounds
Speech of others sounds garbled
The Nose
Smell accounts for about 90% of what we think we taste
Receptors
◦ Olfactory Epithelium
◦ Patch of tissue in the nose
◦ About the size of a postage stamp
◦ Plentiful supply of nerve cells with specialized receptors
◦ Our nose can detect about 10,000 different smells!
Olfactory Nerve
◦ Transmits stimulus to brain
Disorders of the Nose
Nasal Polyps
◦ Growth inside the nasal cavity
◦ Usually associated with rhinitis
◦ If obstructive, may require surgery
Deviated Nasal Septum
◦ Condition which there is a bend in the cartilage structure of the septum
◦ Symptoms include blockage of airflow in one nostril, snoring, nose bleeds, difficulty sleeping
◦ Surgical intervention may be required
The Tongue
Mass of muscle tissue
Papillae
◦ Taste buds
◦ Sweet, Sour, Salty, Bitter
Three cranial nerves transmit stimuli from taste buds to the brain for interpretation
Career Spotlight: Audiologist
Diagnose & Treat hearing problems, including
balance disorders.
Use technology to treat hearing disorders,
including hearing aids and programming
cochlear implants.
Work Settings: Schools, hospitals, private
practice, research agency
Yearly Salary: $52,000-90,000
Job Outlook: Excellent
Education: Doctoral Degree
Career Spotlight: Ophthalmic Lab
Technician
Make prescription eyeglasses and contact
lenses.
Cut, grind, edge, and finish lenses according to
orders from opticians, optometrists, and
ophthalmologists.
Often use automated equipment to make
lenses.
Work Settings: Labs, workshops, large eyeglass
stores. Limited contact with people.
Yearly Earnings: $18,860-43,250
Job Outlook: Excellent
Education: On the job training
Career Spotlight: Dietary Aide
Works in food preparation and food service
programs.
Prepare meals, plan menus, interview patients
about their diets.
Work Settings: Hospitals, Long Term Care
Facilities
Yearly Earnings: $29, 200
Education: High school diploma and on the job
training, certificate programs
Career Spotlight: Patient
Advocate/Navigator
Trained, healthcare workers (often nurses)
who provide support and guidance throughout
the patient’s healthcare process.
Yearly Earnings: Varies by background
Help navigate through appointments,
insurance systems, patient support
organizations, patient research, community
outreach and other components.
Education: Varies by individual facility policies;
often it is a RN or Social Worker which requires
an associate’s degree or bachelor’s degree
respectively.
Work Setting: Hospital, Physicians Office
Job Outlook: Good
The END!